Screen-printed SnO 2 /CNT quasi-solid-state gel-electrolyte supercapacitor

This study investigates a quasi-solid-state gel-electrolyte supercapacitor fabricated with nanoporous SnO 2 /CNT nanocomposite electrodes and a polyvinyl alcohol/sulfuric acid (PVA/H 2 SO 4 ) gel electrolyte. First, pastes containing SnO 2 nanoparticles, CNTs, ethyl cellulose, and terpineol are screen-printed onto carbon cloth. A tube furnace is then used for calcining the SnO 2 /CNT electrodes on carbon cloth. After furnace-calcination, the wettability of SnO 2 /CNT significantly improved; furthermore, the XPS analysis shows that number of C-O bond and oxygen content significantly decrease after furnace-calcination owing to the burnout of the ethyl cellulose by the furnace calcination processes. The furnace-calcined SnO 2 /CNT electrodes sandwich the PVA/H 2 SO 4 gel electrolyte to form a supercapacitor. The fabricated supercapacitor exhibits an areal capacitance of 5.61 mF cm -2 when flat and 5.68 mF cm -2 under bending with a bending radius (R) of 1.0 cm. After a 1000 cycle stability test, the capacitance retention rates of the supercapacitor are 96% and 97% when flat and under bending (R = 1.0 cm), respectively. ? 2017 IOP Publishing Ltd.